Low-permeability reservoir horizontal well same-well synchronous injection-production energy supplementing method

Abstract

The invention relates to the technical field of low-permeability oil reservoir recovery, in particular to a low-permeability oil reservoir horizontal well same-well synchronous injection-production energy supplementing method, which adopts a low-permeability oil reservoir horizontal well same-well synchronous injection-production energy supplementing method pipe column, the pipe column divides a horizontal section of a horizontal well into two sections, and water injection energy supplementing is performed on the horizontal section of a heel end part through an oil pipe and a casing annulus. The method comprises the following specific steps: step 1, carrying out trial extrusion and string verification on a tubular column; 2, a Y445 packer in the tubular column is set; 3, the lower inserting pipe is connected to the pipe column in a tie-back mode; and 4, energy complementing production is conducted through the tubular column. According to the method, water injection and energy supplementation are conducted on the heel end of the horizontal well through the tubular column, the energy of the horizontal well is recovered, meanwhile, the displacement effect between horizontal section seams is achieved, the energy and yield of the horizontal well are improved, meanwhile, the mode of dragging the tubular column can be adopted, injection-production sections are replaced, the near-well water drive effect is continuously improved, and the purpose of improving the recovery efficiency is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of low permeability oil reservoir recovery, and in particular to a method for synchronous injection and production of horizontal wells in low permeability oil reservoirs. Background Art

[0002] Water production and injection in the same well usually uses an inverted electric pump unit in the same well to extract water from the water source layer and then directly inject it back into the target injection layer after pressurization to replenish the energy of the target injection layer. According to production needs, two production and injection methods can be implemented: production above and injection below or production below and injection above.

[0003] An oilfield took the lead in carrying out annular water injection and tubing oil production in vertical wells and directional wells, and completed the evaluation of multiple wells with integrated injection and production test wells, which achieved good results. An oilfield carried out research and application of integrated injection and production technology for horizontal wells, and explored new ways to increase production and transform old oilfield blocks. In order to achieve the goal of sustained and stable production, it is necessary to work on both new production and old production. New production: New crude oil production capacity of about 4-6 million tons per year, and the utilization of geological reserves of about 200 million tons of petroleum, of which more than 50% are geological reserves of ultra-low permeability reservoirs with worse reservoir properties, and it is difficult to establish an effective displacement system. Old oilfield: The comprehensive decline is controlled within 10%. At present, the natural decline of ultra-low permeability reservoirs is 13.7%, and the comprehensive decline is 11.5%. The existing technology can no longer meet the stable production needs of ultra-low permeability reservoirs.

[0004] At present, many oil fields have entered the stage of high production and high water content. Water is produced during the production process of oil wells, which not only seriously affects the oil production, but also loses reservoir energy and reduces the effect of water injection displacement. In order to effectively use the remaining oil as soon as possible, fully tap the potential of the remaining oil, and further optimize the well network within a certain range, the same well injection and production method is studied to find the water-producing layer section, change water plugging into water injection, and produce up and inject down or inject up and produce down, so that the low-yield and severely water-producing oil horizontal wells have water injection functions, so that the underground well network forms an effective displacement, which will be conducive to the successful production of the remaining oil.

[0005] However, in the early stage, vertical well and directional well tests were mainly carried out. There were many horizontal wells in the oil field, with a large decline rate. The oil field has been in a low-yield and low-efficiency production state for a long time, which seriously restricted the stable production of the oil field. Horizontal well energy replenishment has become a technical direction that urgently needs to be tackled, but its method string design is more difficult and the operation method requirements are higher. There is no effective method string and method method yet. Summary of the invention

[0006] In view of the problem that it is difficult to realize energy replenishment in horizontal wells in the prior art, the present invention provides an energy replenishment method for synchronous injection and production in horizontal wells of low permeability oil reservoirs.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for synchronous injection and production of energy replenishment in horizontal wells in low permeability oil reservoirs, characterized in that a pipe string is used for the method, wherein the pipe string comprises a pumping unit, a high-pressure sealing wellhead, a pumping pump, a tubing anchor, a Y445 packer, a cannula sealer, a centralizer and an end tool assembly which are arranged in sequence; the pipe string divides the horizontal section of the horizontal well into two sections, and water is injected to replenish energy in the horizontal section of the heel end through the tubing and casing annulus of the pipe string, and the finger end is used for oil production through the tubing, and the specific steps are as follows:

[0009] Step 1: Test the string by squeezing it;

[0010] Step 2: Set the Y445 packer in the tubing string;

[0011] Step 3: Connect the lower insert back to the pipe string;

[0012] Step 4: Use the pipe string to supplement energy production;

[0013] Step 5: After step 4 is completed, the tubing string is displaced, and the displaced tubing string is used to perform energy replenishment production as in step 4 at the new location.

[0014] Preferably, in step 1, the specific steps are as follows:

[0015] Step 101, assemble and run the pipe string as required, the structure of the pipe string from bottom to top is: packer + pressure gauge nipple + telescopic compensator + check valve + sandblaster + adjustment tubing + leather cup Y445 packer + hydraulic anchor + pressure gauge nipple + one tubing + hydraulic safety joint;

[0016] Step 102, the double-channel pressure gauge test design is used to test the pressure change before and after the test packer. If the pressure before and after the test packer changes synchronously, the seal position and the injection and production section position are replaced until there is no obvious connection outside the casing, which is the effective seal position.

[0017] Preferably, the specific steps of step 2 are as follows:

[0018] Step 201, assemble and run the tubing string as required, the structure of the tubing string from bottom to top is: plug + screen tube + pressure gauge nipple + Y445 packer + hydraulic setting tool + oil pipe to the wellhead;

[0019] Step 202, after confirming that the Y445 packer is set at the correct depth, a steel ball is inserted, and after the ball is in place, the set Y445 packer is pressed to release the packer;

[0020] Step 203, probing down to verify whether the setting of the Y445 packer is reliable;

[0021] Step 204, lifting out the pipe string structure when setting.

[0022] Preferably, in step 203, the verification operation is: drilling down to the Y445 packer position, when the hanging weight of the tubing string drops by more than 30%, it is proved that the Y445 packer is reliably seated.

[0023] Preferably, the specific steps of step 3 are as follows:

[0024] Step 301, assemble and lower the tubing string as required, the structure of the tubing string from bottom to top is: sealing pipe + tubing centralizer + pressure gauge nipple + tubing + tubing anchor + oil pump equipment + tubing to wellhead, and the tubing anchor has built-in shear nails;

[0025] Step 302, when approaching the Y445 packer lowering position, observe the weight indicator of the operating unit, and when the hanging weight of the pipe string decreases, control the downward pressure tonnage, indicating that the cannula has been inserted into the inner hole of the Y445 packer, and sealing is achieved;

[0026] Step 303, start the tubing anchor and anchor the tubing anchor, and verify the anchoring effect of the tubing anchor by lifting the pipe string until the tubing anchor is anchored reliably;

[0027] Step 304, install the water injection wellhead and the wellhead sucker rod intelligent blowout prevention system, install the pumping unit, perform system joint debugging, and then carry out normal production.

[0028] Preferably, in step 303, the verification process of the anchoring of the tubing anchor is: when the hanging weight of the tubing string increases, the tubing anchor is anchored.

[0029] Preferably, in step 4, when replenishing energy, water is injected through the wellhead casing, and the injected water is injected into the heel section through the casing annulus to replenish energy from the root section, thereby establishing interstices displacement between the root section and the remaining finger sections.

[0030] Preferably, in step 4, during production, the formation fluid of the remaining finger section flows into the wellbore, flows into the oil pipe through the screen pipe, then flows through the cannula, enters the oil pump, and the liquid is produced by suction.

[0031] Preferably, in step 5, the specific steps of displacing the tubing string are as follows:

[0032] Step 501, pulling out the production tubing: undo the anchoring state of the tubing anchor by right-turning the tubing or lifting and cutting the shear nails, and then pull the oil pump and the tubing out of the wellbore;

[0033] Step 502, salvage the Y445 packer: the salvage tool needs to be lowered, and the salvage can be successfully achieved by first pressing down and then lifting up. It can be verified by salvaging and lowering the string to the original setting position;

[0034] Step 503, change the displacement section, and lower the displacement string according to the new string design: according to the new segment position, carry out steps 1 to 4 in sequence, lower the Y445 packer into the new position for sealing, and start a new round of energy replenishment production.

[0035] Preferably, in step 502, when verifying the status of the Y445 packer, if the packer is unsealed, the salvage load is the deadweight of the tubing string, and the tubing string can be pulled out in sequence; if the salvage load is greater than the deadweight of the tubing string, the previous pressing process is repeated to verify the unsealing status of the packer.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention provides a method for synchronous injection and production of energy replenishment in horizontal wells in low permeability oil reservoirs. The method uses a pipe string to inject water to the heel end of the horizontal well to replenish energy, restore the energy of the horizontal well, effectively replenish the energy of the low-pressure and low-yield layer section, and restore the reservoir energy, thereby establishing effective displacement between horizontal well sections, improving the production and recovery rate of the horizontal well, and at the same time realizing the energy replenishment at the heel end, displacement of the finger end oil, synchronous production at the finger end, and production of formation liquid, realizing synchronous displacement production between different sections of the same well without stopping the well, effectively restoring the production capacity of the horizontal well, and providing an effective production-increasing technical means for low-yield horizontal wells. In addition, the method of dragging the pipe string can be used to replace the injection and production section, continuously improve the water drive effect near the well, and achieve the purpose of improving the recovery rate.

[0038] Furthermore, through string verification, the connection between different sections can be effectively judged, and the injection and production sections that can establish displacement and form water drive effects can be selected to improve the success rate and effect of simultaneous injection and production in the same well. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of a pipe string in a method for synchronous injection and production energy replenishment of horizontal wells in a low permeability oil reservoir according to the present invention.

[0040] Figure 2 The present invention is a flow chart of a method for synchronous injection and production energy replenishment of horizontal wells in a low permeability oil reservoir.

[0041] In the figure, 1. Pumping unit; 2. High-pressure sealed wellhead; 3. Pumping pump; 4. Tubing anchor; 5. Y445 packer; 6. Intubation sealer; 7. Centralizer; 8. End tool assembly. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0043] The present invention discloses a method for synchronous injection and production of energy replenishment for horizontal wells in low permeability oil reservoirs. Figure 1As shown in the figure, the pipe string structure includes a pumping unit, a high-pressure sealed wellhead, a pump, a tubing anchor, a Y445 packer, a tubing sealer, a stabilizer, and an end tool assembly. The pipe string divides the horizontal section of the horizontal well into two sections, and water is injected into the horizontal section at the end through the tubing and casing annulus to effectively restore the formation energy. At the same time, the finger end is used for oil production through the tubing, changing the near-well fluid flow trend and energy distribution of the crude oil, so as to expand the swept volume and improve the crude oil recovery rate.

[0044] Among them, the oil pump is a tubular pump, which can realize the water injection process and normal oil production in the wellbore.

[0045] The high-pressure sealed wellhead adopts a high-pressure valve design. During the initial water injection process, the pressure is relatively low due to the energy deficit of the formation. However, as the water injection time increases, the pressure will gradually increase, and the risk of simple wellhead well control is relatively large.

[0046] The tubing anchor structure includes an upper joint, an anchoring support mechanism, a two-way slip, a seat lock tightening mechanism, and a lower joint. The tubing anchor is lowered into the wellbore along with the tubing string and connected to the bottom of the oil pump. The tubing string is rotated to seal the two-way slip seat and anchor the tubing. When unsealing, the tubing string is lifted up to cut off the unsealing pin in the anchoring support mechanism and unseal it, and then it is lifted up out of the wellbore. The function of the tubing anchor is to anchor the tubing to prevent the unsealing failure of the tubing string caused by suction during the production of the oil pump.

[0047] The structure of the Y445 packer includes a lower joint, a seal pushing mechanism, a seal rubber tube combination, a two-way slip, a release joint, an unsealing pin, and an inner connecting tube. The release joint connects the Y445 packer to the oil pipe and lowers it into the wellbore. After the seal is pressed, the hand is lifted to place the Y445 packer at the bottom of the well. The lower joint is used to connect the horizontal section tail pipe production string. The seal pushing mechanism is mounted on the inner connecting tube, and the lower end is connected to the lower joint. When the tool reaches the predetermined position, the string is pressurized, and the seal pushing mechanism pushes the seal rubber tube combination and the two-way slip to open, and the seal is at the predetermined position of the casing. The Y445 packer needs to be lowered into the wellbore with a special tool for docking and unsealing. The inner connecting tube is designed with high-hardness, low-roughness stainless steel to establish an effective sealing surface for the insertion tube.

[0048] Before the Y445 packer is lowered into the wellbore for sealing, a test string needs to be lowered and the wellbore pressure is stimulated on the ground. The test tool adopts a dual-channel pressure gauge test design to test the pressure changes before and after the packer. If they change synchronously, it means that there is a pressure connection outside the casing and effective displacement cannot be achieved. The sealing position and the injection and production section position need to be changed until there is no obvious connection outside the casing, which is the effective sealing position.

[0049] The intubation sealer includes a tubing connector, a sealing rubber ring, an anti-creeping slip, a primary sealing nipple, a long-term sealing rubber ring, a sealing rubber ring, a secondary sealing nipple, and a guide head. The tubing connector is used to connect the upper tubing and connect it to the wellbore to achieve the connection of the lower section of the tubing string; the anti-creeping slip is at the upper end of the intubation sealer to fix the tubing string and prevent it from creeping out; the primary sealing nipple, the long-term sealing rubber ring, the sealing rubber ring, and the secondary sealing nipple jointly establish a sealing mechanism, which forms an effective dynamic sealing state with the connecting tube inside the Y445 packer, achieving reliable dynamic sealing inside and outside the tubing.

[0050] The centralizer is connected to the lower end of the Y445 packer to centralize the tail tubing and extend the effective period of the tubing string seal.

[0051] The end tool combination includes a ball seat, a soluble metal plug, a wire-wound sand screen, and a dead plug. The end tools can meet the functions of sealing the pipe string packer, outflow of produced fluid, anti-spitting, and sand plugging the pipe string. The ball seat is designed at the top to prevent the liquid in the oil pipe from flowing back to the formation; after the soluble metal plug is lowered, the soluble metal plug is in a closed state. When the packer is sealed, the soluble metal contacts the wellbore liquid and gradually dissolves, connecting the ball seat with the wire-wound sand screen; the wire-wound sand screen adopts a cross-wire structure design to prevent sand from entering the wellbore. The dead plug is connected to the end of the pipe string to prevent large mud and sand from entering the oil pipe.

[0052] The present invention also discloses a method for synchronous injection and production of energy in horizontal wells of low permeability oil reservoirs, referring to Figure 1 , 2 The pipe string divides the horizontal section of the horizontal well into two sections. Water is injected into the horizontal section at the heel end through the tubing and casing annulus, and oil is produced at the finger end through the tubing. Taking a horizontal well in a low permeability reservoir as an example, the specific steps of its injection and production energy replenishment method are described.

[0053] Step 1: Test the string

[0054] Step 101, assemble and lower the tubing string as required. The tubing string structure from bottom to top is: Y445 packer + pressure gauge short section + telescopic compensator + check valve + simple sandblaster + adjustment tubing + leather cup Y445 packer + hydraulic anchor + pressure gauge short section + a tubing + hydraulic safety joint.

[0055] Step 102: Press and unlock the squeeze cup Y445 packer. The 700 pump truck continues pumping for 20m 3 The wellbore was filled, and the highest pump pressure was only 4MPa. The Y445 packer was set by lifting and lowering the pipe string, and 10 tons of drilling pressure was applied. The tubing was pumped, and the annulus returned liquid. There was no sign of setting the upper seal. Then two 700-type pump trucks were connected in parallel, and the casing gate was opened. The maximum pressure in the tubing reached 24MPa, and the pressure drop was not obvious. A 30m test was conducted. 3Active water, no liquid returns to the casing annulus, and the pump-stop pressure in the oil pipe is about 2MPa after the pump is stopped, indicating that the upper seal has been set.

[0056] Step 2: Y445 Packer Setting

[0057] Step 201, assemble and lower the tubing string as required, and the tubing string structure from bottom to top is: plug + screen tube + pressure gauge nipple + Y445 packer + hydraulic setting tool + oil pipe to the wellhead.

[0058] Step 202, set the Y445 packer, after confirming that the Y445 packer setting depth (avoiding the casing coupling) is correct, put in the steel ball, and after the ball is in place, pressurize and set the Y445 packer. Pressurize to 10MPa and maintain the pressure for 5 minutes, pressurize to 12MPa and then drop the pressure to 2MPa, and the packer is released.

[0059] Step 203: Drill down to verify the Y445 packer is set. When drilling down to the Y445 packer position, the hanging weight of the tubing string is reduced from 30KN to 20KN, proving that the Y445 packer is reliably set.

[0060] Step 204: lift out the sealing string.

[0061] Step 3: Lower the cannula and connect the pipe string

[0062] Step 301: Assemble and lower the tubing string as required. The tubing string structure from bottom to top is: sealing tube + tubing centralizer + pressure gauge nipple + tubing + tubing anchor + oil pump equipment + tubing to wellhead. The tubing anchor has 7 shear nails built in, and the shear force is about 14 tons.

[0063] Step 302, when approaching the Y445 packer lowering position, observe the weight gauge, when the hanging weight of the pipe string decreases, control the downward pressure tonnage to 6 tons, indicating that the plug has been inserted into the inner hole of the Y445 packer, and the seal is achieved. The purpose of loading 6 tons of drilling pressure on the sealing plug is to prevent the sealing plug from slipping during oil production operations.

[0064] Step 303, start the tubing anchor. Use the tubing tongs to turn the tubing counterclockwise for 5 turns, and the tubing anchor is anchored. The anchoring effect of the tubing anchor is verified by lifting the pipe column. The hanging weight increases from 30KN to 36KN, proving that the tubing anchor is anchored reliably.

[0065] Step 303: Install the water injection wellhead and the wellhead pump rod intelligent blowout prevention system, install the pumping unit, and perform system joint debugging. Then, normal production is carried out.

[0066] When the production string needs to be pulled out later, the shear nails can be cut by right-handed rotation of the string 4-8 times or lifting about 29 tons to release the anchor state of the tubing anchor. To salvage the Y445 packer, the salvage tool needs to be lowered, pressed down by 5-8 tons, and then lifted up to achieve successful salvage. It can be verified by lowering the string after salvaging and passing the original sealing position.

[0067] Step 4: Energy production

[0068] During energy replenishment, water is injected through the wellhead casing, and the injected water is injected into the heel section through the casing annulus, energy is replenished from the root section, and displacement between the root section and the remaining finger section is established. During production, the formation fluid of the remaining finger section flows into the wellbore, flows into the oil pipe through the screen pipe, and then flows through the cannula and enters the oil pump, and the liquid is extracted by suction.

[0069] Step 5: After step 4 is completed, the pipe string is displaced, and the displaced pipe string is used to perform energy replenishment production as in step 4 at a new location.

[0070] Step 501, pulling out the production tubing: undo the anchoring state of the tubing anchor by right-turning the tubing or lifting and cutting the shear nails, and then pull the oil pump and the tubing out of the wellbore;

[0071] Step 502, salvage the Y445 packer: the salvage tool needs to be lowered, and the salvage can be successfully achieved by first pressing down and then lifting up. It can be verified by salvaging and lowering the string to the original setting position;

[0072] Step 503, change the displacement section, and lower the displacement string according to the new string design: according to the new segment position, carry out step 4, lower the Y445 packer into the new position for sealing, and start a new round of energy replenishment production.

[0073] The invention discloses a method for synchronous injection and production energy replenishment of horizontal wells in low permeability oil reservoirs. The method uses a pipe string to inject water to replenish energy at the heel end of the horizontal well, thereby restoring the energy of the horizontal well and realizing the displacement effect between the horizontal sections, thereby improving the energy and production of the horizontal well. At the same time, the method can adopt the method of dragging the pipe string to replace the injection and production sections, thereby continuously improving the water drive effect near the well and achieving the purpose of improving the recovery rate.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A method for synchronous injection and production of energy in horizontal wells of low permeability oil reservoirs, characterized in that: The method of synchronous injection and production of low permeability reservoir horizontal wells is adopted. The string includes a pumping unit, a high-pressure sealing wellhead, a pumping pump, a tubing anchor, a Y445 packer, a plug sealer, a centralizer and an end tool combination arranged in sequence; the string divides the horizontal section of the horizontal well into two sections, and water is injected to replenish energy in the horizontal section at the heel end through the tubing and casing annulus of the string, and oil production is carried out through the tubing at the finger end; The specific steps of injection and production are as follows: Step 1: Test the string by squeezing it; Step 2: Set the Y445 packer in the tubing string; Step 3: Connect the lower insert back to the pipe string; Step 4: Use the pipe string to supplement energy production; Step 5: After step 4 is completed, the tubing string is displaced, and the displaced tubing string is used to perform energy replenishment production as in step 4 at the new location.

2. The method for synchronous injection and production of horizontal wells in low permeability oil reservoirs according to claim 1, characterized in that: In step 1, the specific steps are as follows: Step 101, assemble and run the pipe string as required, the structure of the pipe string from bottom to top is: packer + pressure gauge nipple + telescopic compensator + check valve + sandblaster + adjustment tubing + leather cup Y445 packer + hydraulic anchor + pressure gauge nipple + one tubing + hydraulic safety joint; Step 102, the double-channel pressure gauge test design is used to test the pressure change before and after the test packer. If the pressure before and after the test packer changes synchronously, the seal position and the injection and production section position are replaced until there is no obvious connection outside the casing, which is the effective seal position.

3. The method for synchronous injection and production of horizontal wells in low permeability oil reservoirs according to claim 1, characterized in that: The specific steps of step 2 are as follows: Step 201, assemble and run the tubing string as required, the structure of the tubing string from bottom to top is: plug + screen tube + pressure gauge nipple + Y445 packer + hydraulic setting tool + oil pipe to the wellhead; Step 202, after confirming that the Y445 packer is set at the correct depth, a steel ball is inserted, and after the ball is in place, the set Y445 packer is pressed to release the packer; Step 203, probing down to verify whether the setting of the Y445 packer is reliable; Step 204, lifting out the pipe string structure when setting.

4. The method for synchronous injection and production of horizontal wells in low permeability oil reservoirs according to claim 3 is characterized in that: In step 203, the verification operation is: drilling down to the Y445 packer position, when the hanging weight of the tubing string drops by more than 30%, it is proved that the Y445 packer is reliably seated.

5. The method for synchronous injection and production of horizontal wells in low permeability oil reservoirs according to claim 1, characterized in that: The specific steps of step 3 are as follows: Step 301, assemble and lower the tubing string as required, the structure of the tubing string from bottom to top is: sealing pipe + tubing centralizer + pressure gauge nipple + tubing + tubing anchor + oil pump equipment + tubing to wellhead, and the tubing anchor has built-in shear nails; Step 302, when approaching the Y445 packer lowering position, observe the weight indicator of the operating unit, and when the hanging weight of the pipe string decreases, control the downward pressure tonnage, indicating that the cannula has been inserted into the inner hole of the Y445 packer, and sealing is achieved; Step 303, start the tubing anchor and anchor the tubing anchor, and verify the anchoring effect of the tubing anchor by lifting the pipe string until the tubing anchor is anchored reliably; Step 304, install the water injection wellhead and the wellhead sucker rod intelligent blowout prevention system, install the pumping unit, perform system joint debugging, and then carry out normal production.

6. The method for synchronous injection and production of energy in horizontal wells in low permeability oil reservoirs according to claim 5, characterized in that: In step 303, the verification process of the anchoring of the tubing anchor is: when the hanging weight of the tubing string increases, the tubing anchor is anchored.

7. The method for synchronous injection and production of energy in horizontal wells in low permeability reservoirs according to claim 1, characterized in that: In step 4, when replenishing energy, water is injected through the wellhead casing, and the injected water is injected into the heel section through the casing annulus to replenish energy from the root section and establish inter-fracture displacement between the root section and the remaining finger sections.

8. The method for synchronous injection and production of energy in horizontal wells in low permeability reservoirs according to claim 1, characterized in that: In step 4, during production, the formation fluid of the remaining finger section flows into the wellbore, flows into the oil pipe through the screen pipe, then flows through the cannula, enters the oil pump, and the liquid is produced by suction.

9. The method for synchronous injection and production of energy in horizontal wells in low permeability oil reservoirs according to claim 1, characterized in that: In step 5, the specific steps of column displacement are as follows: Step 501, pulling out the production tubing: undo the anchoring state of the tubing anchor by right-turning the tubing or lifting and cutting the shear nails, and then pull the oil pump and the tubing out of the wellbore; Step 502, salvage the Y445 packer: the salvage tool needs to be lowered, and the salvage can be successfully achieved by first pressing down and then lifting up. It can be verified by salvaging and lowering the string to the original setting position; Step 503, change the displacement section, and lower the displacement string according to the new string design: according to the new segment position, carry out steps 1 to 4 in sequence, lower the Y445 packer to the new position for sealing, and start a new round of energy replenishment production.

10. The method for synchronous injection and production of horizontal wells in low permeability oil reservoirs according to claim 9, characterized in that: In step 502, when verifying the status of the Y445 packer, if the packer is unsealed, the salvage load is the deadweight of the tubing string, and the tubing string can be pulled out in sequence; if the salvage load is greater than the deadweight of the tubing string, repeat the previous pressing process and verify the unsealing status of the packer.

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